Distant-communication cable



Jan. 1, 1929.`

E. FISCHER DISTANT GOMMUNICATIONCABLE Filed Jan. 13, 1927 LAMA v fife@ Jfffsfff if; a

*Paie-mea Jan. 1, 1929.

UNITED STATES" `PATENT OFFICE.

ERTWEEKE GESELLSCHAFT MIT BESCHRNKTER HAFTUNG, lOil BEBLIl-BIEMENBY- STADT, GERMANY, A COPOBATION OF GERMANY.

INSTANT-COMMUNICATION CABLE.-

i Application led January 13, 1927, Serial No. 160,950, and in Germary October 6, 1925.

` have as high a degree of permeability as possible. It is, however, known that the permeability of such materials is reduced, if they are subjected to a. tensile stress, even a slight one. In the annealing process necessary in the manufacture of cables after winding the magnetic material upon the copper conductor considerable stresses are set up in the magnetic material wound upon the conductor owing to the different coeiiicients of expansion of the copper and the magnetic ma.- terial, usually steel or iron, so that the permeability of the magnetic material is considerably reduced and its magnetic properties suii'er thereby.

This drawback is 'eliminated by m linvention according to which the magnetlc material is wound upon the conductor as a corrugated or otherwise suitably shaped tape or wire. When employing such a ribbon or wire the tensile stress set up during the annealing processes owing to the greater expansion vof the co perconductor will only cause a slight straig tening out or reduction of the amplitude of the corrugations or waves of the mai terial without the material' itself being subjected to any tensile stress. Asit. is difficult to wind corrugated ribbon or wire Ainto a reel and to unwind it again, a smooth ribbon or wire is preferably passed through acorrugating device on its way to the copper conductor, so that the shape desired is onlyimits application to the copper conductor.

I have illustrated my invention in the accompanying drawings in which Fig. 1 illustrates a corrugating device for the material.

Fig. 2 illustrates a corrugated ribbon applied helically to the cable conductor.

Fig. 3 illustrates -a corrugated Wire helically applied to the cable conductor.

die, such as is shown at 10 in Fig. 4. .This

flattens out any prominent portions of the 'wrapping as shown at 12, and reduces the outer .diameter of the wrapping to uniform sizeA as shown at 11 in Fig. 4;. In this way very uniform corrugations are obtained in the magnetic covering.

The magnetic material may of course, be bent into other vsuitable shapes than simple corrugations, ,for instance into U-shape, so.

long as no stressing of the material but only a cha-.nge in its shape takes place when the conductor around which it is wrapped eX- pands. It will be understood that in this case also it is advantageous to start with a straight ribbon or wire and only to bend. it into the U-'shape immediately before its application to the conductor, by passing it through a suitable device.-

Various modifications and changes may be made without 'departing from the spirit and the scope of the invention, and I desire, therefore, that only vsuch limitations shall be art.

I .claim as my invention 1. In a line cable having a constant distributed self inductance, a covering for the conductor consisting of a corrugated ribbon of 'magnetic material of high permeability. parted to thepmaterial immediately before 2. In a line cable having a. constant disl tributed self inductance, a covering wound on the conductor and consisting of corrugated magnetic material of high permeability.

3. In the method of making a line cable having a constant distributed self inductance, the passing of a straight length of magnetic material of high permeability through a corrugating device and applying the rrugated placed thereon as are imposed by the prior material heiicaliy to the conductor 'as it leaves the corrugating device and drawing the covthe corrugating device.

ered conductor through a compressing die. 10 4. In the method of malnng a line cable 5'. As a. new article of manufacture, a line having a. constant distributed self inductance, cable comprising a conductor having a helithe passing of a straight length of magnetic cally applied iron corrugated ribbon.

material of high permeability through a cor- In testimony whereof I aix my signature. mgating device and applying the Corrugated material helically to the 'conductor as it leaves ERNST FISCHER. 

